Shoe stiffener and method of manufacturing the same



Sept. 12, 1933. MELLERIO 1,926,161

SHOE STIFFENER AND METHOD OF MANUFACTURING THE SAME Filed June 29, 19512 Sheets-Sheet l Avg/70H m P W Sept. 12, 1933. p, MELLERIO 1,926,161

SHOE STIFFENER AND METHOD OF MANUFACTURING THE SAME FiledvJune 29, 19312 Sheets-Sheet 2 WI/E/VTUF mhm Patented Sept. 12, 1933 UNITED STATES-PATENT OFFICE sHoE STIFFENER AND METHOD OF MANUFACTURING 'THE SAMEApplication June 29, 1931, Serial No. 547,565, and in Great Britain July10, 1930 20 Claims. (CI. 36-77) V This invention relates to shoestiffeners having a porous base which carries a stiifening substance andto methods of manufacturing them, and will be described, by way ofillustration, as embodied in a toe stiffener of the so-called semi-softtype and with especial reference to the manufacture of such stiffeners.

In stiffeners of this type it is desirable to provide a greater amountof stiffening substance per unit volume in that portion which, in thefinished shoe, will extend around the sides and end of the toe portionof the shoe and for a certain distance up from the junction of the upperwith the sole, and to provide a less amount per unit volume in thatportion of the stiffener which is uppermost in the finished shoe. Thetoe portion of the shoe will thus be very stiff and hard around thesides and end butwill be quite flexible and resilient on the top. It isalso desirable that a considerable portion at least of a toe stiffener,whether or not it is of this general type in which certain portions aremore flexible than others, should be sufficiently pervious to permitdiffusion of air and moisture outwardly from the inside of the shoeduring wear; and the present invention provides a method whereby eitheror both of these desirable results may be attained.

In one aspect the method of thisinvention comprises subjecting astiffener blank having a.

, porous base, which carries a stiffening substance,

to pressure to expel stiffening substance from a selected locality andto transfer it to another locality. In the case of a semi-soft stiffenera 5 blank carrying a uniformly distributed load of stiffening substance,such for example as a mixture of colophony and Montan wax which isthermoplastic, may advantageously be subjected to heat and pressure bymeans of suitably formed rollers to expel some of the substance from themiddle portion of the blank and to transfer it to a generallycrescent-shaped locality lying along but spaced from the front and sideedges thereof. There may thus be produced from an.- ordinarythermoplastic stiffener Which wasori'ginally'of a uniform stiffnessthroughout a semiesoft stiffener.

In another aspect the invention comprisesa method of rendering astiifenen or a selected locality of a stiffener, pervious toair andmoisture. This locality may be the middle locality of a semisoftstiffenerof the type referred to above; and this result may be producedby suitably control ling the conditions of heat and pressure. To thisend, a heat of suitable temperature to reduce the stiffening substanceto a proper consistence is preferably employed, and a pressure of. aforce and duration is used just sufficient to' expel a certain amount'ofstiffening substance without permanently consolidating the fabric base.Thus, after the pressure has beenwithdrawnand before the stiffener hascooled, the fibres of the fabric will spring back to or toward theiroriginal positions so that pores or cracks will be formed in thecomparatively small amount per unit volume of stiffening substance whichremains after the expelling operation. 7

The invention also comprises a novel stiffener which may result from thepractice of the method, and which, as herein illustrated, ischaracterized by having a porous. base impregnated with a Referring nowto the accompanying drawings,

Fig. 1 is a plan of a toe stiffener made in accordance with the methodof the invention;

Fig. 2 is a section onthe line II--II of Fig. 1; Fig. 3 is a section onthe line IIIIII of Fig. l;

Fig. 4 is a plan of a modified form of toe stiffener; and

Fig. 5 is a section on the line VV of Fig. 4.

For producing a semi-soft toe stiffener, a suitably shaped blank may becut to outline from the cold, hard impregnated'sheet in the usual way.Assuming that the stiffener is for use in a mans shoe, and has a lengthof say 3 inches on the line 11-11 and a width of say 4 inches on theline III-III of Fig. 1, it may conveniently be cut from sheet fabriccomposed of porous sheet material of say 65 to '70 thousandths. of aninch in thickness before impregnation, impregnated with the usual typeof thermoplastic, stiffening substance and calendared to be in the coldhard condition of a fairly uniform thickness of say liam J. Lund, andMaurice G. Hill, may be em- For example, the apparatus shown in ployed,with a suitably shaped die in the die roller and with the rollingpressure and. the tem peratureso controlled that. the following resultsare obtained, There is expelled from the entiremargin enough stiffeningsubstance so that a comparatively thin beveled margin results. Expulsionof stiffening substance. is also caused to occur to a considerableextent from all portions of the blank except from a, crescent-shapedlocality indicated in Fig. 1 by a dot-and-das'h line. In

this locality the blank actually is. left so heavily charged with,stiffening substance that on both its faces, though'to differingextents, there is. (see a, b, Figs, 2. and 3) 'a crescent-shaped surfacedeposit of excess substance, As better illustrating the form :of the dieused in sucha case during the hot-pressure treatment, the followingparticulars may be given regarding the thickness of one such treatedblank when it has become cold and stiff. Y

Thousandths of an inch at points 0 Fig. 1-about at points (i Fig. 1aboutat points a Fig 1-about at points f Fig. 1-about at point g Fig. 1-aboutat points h Fig. l-.about at points 70 Fig. 1about at points Z Fig.L-about j shaped locality, it will be tough and flexible having none ofthat hard,unyielding and somewhat brittle character which is a' commonattribute of the main portion of thermoplastic blanks as hitherto made.Moreover, over most of said tough and flexible locality the blank willbe so porous as relatively freelyto admit of the flow of air through itfrom one face to the other. This latter result is apparently due to theexpulsion, without such excessive pressure as permanently to consolidatethe cloth itself to an undue degree, of a sufliciency of stiffeningsubstance to prevent the interstices of the fabric remaining filled withthe substance when, after the pressure is relieved, the'blank expandsbefore it chills and sets hard. These stated characteristics oftoughness and flexibility of the stiffener, within the localityindicated, are apparently more or less completely retained in thestiffener in the finished shoe in spite of the heating to which thestiffener is subjected for the lasting operations and of the tensionsand pressures to which the softened stifiener is exposed during theseoperations which inevitably to some extent displace the softenedstiffening substance. Such displacement appears, however, to resultprincipally in an absorption of stiffening substance from'the heavilycharged crescent-shaped lo'calityby the upper materials in immediatecontact therewith and a consequent disappearance of any perceptibleundue thickness of the stiffener at that part. In the finished shoe, thestiffened toe is very stiff and hard around the sides and end of the toefor a certain distance up from the junction of the upper and so1e,the'outer marginal portion of the stiffener between its outer edge and saidcrescent-shaped locality furnishing the part of the stiffener which islasted over upon the shoe bottom. The stiffener, however, is quitepliable and leathery on the top of the toe portion of the shoe.Conveniently, to ensure the correct location of the said crescent-shapedlocality of the stiffener with reference to the shoe upper during thelasting operations the stiffener and upper are fused togetherpreparatory to the pulling-over operation by the employmentof a suitableheated press of usual construction. In such case it may be preferred tofacilitate such union of stiffener and upper without depending upon anyconsid-' erable heating or pressing of the stiffener in the press exceptat portions of the stiffener which will be on the shoe bottom in thefinished shoe;

and this can be provided for by so forming the the blank, thesespots'being located respectively in the two angles included between therear edge and the side edges of the stiffener;

P In some instances, when the toe stiffener is attached to the upperonly by its corners as just been described, it may happen that, afterthe shoe has been completed and subjected to wear, there will be atendency for the rear mar- I gin of the stiffener between the endsthereof to part company from the adjacent portion of the upper so thatwrinkles are produced across the toe portion of the upper. In order toavoid this possibility the hot rolling-die, by which the stiffener isfirst subjected to heat and pressure, maybe so formed that a thickenedband of stiffening substance may be caused to extend across thestiffener close to the rear edge of the stiffener, the outline of such aband being indicated by the dotted lines '7 and 9m Fig. 4. In

this figure the thickness at the points indicated by the references 0,e, f, g, h, k and Z may be substantially the same as at the pointsindicated by the same references with regard to Fig. 1. This band orlocality will preferably, as shown, he narrower at the mid line (VV) ofthe stiffener and also of somewhat lesser thickness than the maincrescent-shaped locality, the thickness at the point g in the localitybeing about the same as that of theepoint g previously indicated. Whilesuch a narrow locality as last described will in most instances securedue adhesion of the stiffener in the shoe and at the same time avoidgiving undesired stiffness across the top of the toe when the stiffeneris fused intoan upper, it is contemplated that, where circumstances-mayrequire a greater assurance against undue stiffening by such materialwhich is furnished purely for securing adhesion, separated areas orspots positioned substantially along the line of the band may be used tosecure the adhesionrequired instead of a continuous band. Although theinvention has been described in connection with the manufacture of a toestiffener comprising a porous base impregnated with thermoplasticmaterial, it should be understood that the invention is not limited inthe scope of its application to such stiffener or to such manated with astiffening substance to pressure to cause the stiffening substance to beexpelled fromone locality of the blank and to be transferred to anddeposited permanently in another locality of the blank.

2. The method of making a shoe stiffener which comprises subjecting asuitably shaped blank'of porous sheet material impregnated with .astiffening substance to pressure in such manner as to expel stiifeningsubstance from the middle portion of the blank and to depositpermanently the expelled stiffening substance in a locality the outeredge of which is spaced from an edge of the blank.

3. The method of, making a shoe stiffener .which comprises subjectingasuitably shaped blank of porous sheet material impregnated with astiffening substance topressurein such manner as to expelstiffeningsubstance from middle and marginal portions'of the blank and to depositpermanently the expelled stiffening substance in a locality an outeredge of which lies along but is spaced from an edge ofthe blank.

4. The method of making a shoe stiffener which comprises subjecting asuitably shaped blank of porous material impregnated with a stiffeningsubstance to rolling pressure in such a manner as to expel stiffeningsubstance from one locality and deposit it permanently in anotherlocality of the blank.

5. The method of making a shoe stiffener which comprises preparing asuitably shaped blank of porous sheet material impregnated with athermoplastic substance and subjecting the blank to heat and pressure insuch manner as to expel thermoplastic substance from the marginal andmiddle portions of the blank and to deposit said expelled thermoplasticsubstance permanently in a comparatively narrow locality lyingsubstantially parallel to that edge of the blank which is to be bentover upon the bottom of the shoe during the lasting operation.

6. The method of making a toe stiffener which comprises preparing asuitably shaped blank of porous sheet material impregnated with athermoplastic substance and subjecting the blank to heat and pressure insuch manner as to expel thermoplastic substance from the marginal andmiddle portions of the blank and to deposit said expelledthermoplasticsubstance permanently in a curved locality lying substantially parallelto the front and side edges of the blank.

'7. The method of making shoe stiffeners which comprises subjecting aselected locality of a suitably shaped blank of porous sheet materialimpregnated with a thermoplastic stiffening which renders said materialsubstantially impervious to air and moisture to pressure in such manneras to expel sufficient substance from said locality to render thatlocality pervious to air and moisture, and to transfer the expelledsubstance permanently to another locality.

8. The method of making shoe stiffeners which comprises impregnatingporous sheet material with a stiffening substance which renders thematerial substantially impervious to air and moisture, and subjecting alocality spaced from the edge thereof to pressure so applied as torender that locality pervious to air and moisture.

9. The method of making shoe stiffeners which comprises impregnatingporous sheet material with a stiffening substance which renders saidmaterial substantially impervious to air and moisture, and expellingsufficient substance from a selected locality in such manner as torender that locality pervious.

10. The method of making shoe stiffeners which comprises impregnatingporous sheet material with a stiffening substance which renders thematerial substantially impervious to air and moisture, subjecting aselected locality for a predetermined interval to heat and to rollingpressure sufficient to expel some of the substance but insufficient toconsolidate the sheet material, and then withdrawing the pressure andheat to permit the released fibres to pull the substance adjacent tothem apart to form passages through the substance.

11. A shoe stiffener comprising a porous base impregnated with astiffening substance which is impervious to air and moisture, saidsubstance in a locality spaced from the margin of the stiffener beingdiscontinuous sufficiently to be pervious.

I in a locality in the middle portion of the stiffener beingdiscontinuous sufficiently to be pervious,

12. A shoe stiffener comprising aporous base impregnated with athermoplastic stiffening substance which is impervious to air andmoisture, said substance in a locality spaced from the margin of thestiffener being discontinuous sufficiently to be pervious.

13. A shoe stiffener comprising a porous base impregnated with astiffening substance which is impervious to air and moisture, saidsubstance there being located between said locality and the edge of thestiffener a narrow locality containing an excess of stiffeningsubstance.

14. A shoe stiffener comprising. a porous base impregnated with astiffening substance which is impervious to air and moisture, thequantity of stiffening substance per unit volume in that portion of thestiffener which in the finished shoe will be uppermost being less thanin portions adjacent to the edge of the stiffener and having asufficient number of passages through it to render said first-namedportion pervious.

15. A shoe stiffener comprising a porous base and a thermoplasticimpregnating substance, a locality one edge of which extendssubstantially parallel to an edge of the stiffener containing a quantityof stiffening substance per unit volume sufficient to render thatlocality stiff and impervious to air and moisture, and a second localitylocated nearer to the center of the blank containing a lesser amount ofstiffening substance per unit volume, said lastnamed locality beingcomparatively soft and resilient and pervious to air and moisture.

16. A shoe stiffener having a comparatively thin and flexible middleportion completely surrounded by a thicker and less flexible portion.

17. A shoe stiffener having a comparatively thin and flexible middleportion completely surrounded by a thicker and less flexible portion,said last-named portion being spaced from the edge of the stiffener.

18. A shoe stiffener having a comparatively thin and flexible middleportion completely sur- 129 rounded by a thicker and less flexibleportion, said last-namedportionbeing spaced from the edge of thestiffener and said edgebeing at least as thin and flexible as saidmiddle portion.

19. The method of making shoe stiffeners which comprises impregnatingfibrous sheet material with a stiffening substance which renders thematerial substantially impervious to air and moisture, subjecting aselected locality for a predetermined interval to heat and pressuresufli- 130 cient to expel some of the substance but insufficient toconsolidate the sheet material, and then withdrawing the. pressure andheat to permit the released fibres to pull the substance adjacent tothem apart so as to form passages through the substance.

20. A shoe stiffener made from porous material impregnated with astiffening substance, said stiffener having a middle portion of a giventhickness, a rear edge the thickness of which does not exceed that ofthe middle portion, and two small portions of greater thickness thanthat of the middle portion, said two small portions being locatedrespectively in the two angles included between the rear and the sideedges of the stiffener.

LUCIEN PAUL MELLERIO.

